A vagina that tastes so bad that you have to eat a different vagina because it is the only thing that can get the awful taste out of your mouth.

Tom: I ate this girl out the other day and I can't get the awful taste out of my mouth no matter how many times I brush my teeth.
Dick: You gotta go eat out a different chick.
Tom: Why's that?
Dick: The only way to rid yourself of the taste of a Nasty Pistachio is to eat a different one out of the bag.